KR20190106744A - Quantum dot device and electronic device - Google Patents

Abstract

The present invention relates to a quantum dot element and an electronic device, wherein the quantum dot element comprises: an anode and a cathode facing each other; a quantum dot layer located between the anode and the cathode; and an electron transport layer located between the cathode and the quantum dot layer. The quantum dot layer includes a light emitting quantum dot which emits light in at least some wavelength region of a visible light region, and a non-light emitting quantum dot which does not emit light in the visible light region. A difference of LUMO energy levels between the non-light emitting quantum dot and the electron transport layer is 0.5 eV or more. Therefore, the present invention provides a quantum dot device with an improved performance.

Description

Quantum dot device and electronic device {QUANTUM DOT DEVICE AND ELECTRONIC DEVICE}

The present invention relates to a quantum dot device and an electronic device.

Unlike bulk materials, nanoparticles can control physical properties (energy bandgap, melting point, etc.), which are known as intrinsic properties of materials, according to particle size. For example, semiconductor nanocrystals, also called quantum dots, may receive light energy or electrical energy to emit light having a wavelength corresponding to the size of the quantum dots. Accordingly, the quantum dot may be used as a light emitting device that emits light of a predetermined wavelength.

Recently, researches on quantum dot devices using quantum dots as light emitters have been conducted. However, since the quantum dot is different from the existing light emitter, a new method for improving the performance of the quantum dot device is required.

One embodiment provides a quantum dot device capable of implementing improved performance.

Another embodiment provides an electronic device including the quantum dot device.

According to one embodiment, an anode and a cathode facing each other, a quantum dot layer located between the anode and the cathode, and an electron transport layer located between the cathode and the quantum dot layer, the quantum dot layer of the visible light region It provides a quantum dot device comprising a light emitting quantum dot emitting at least a portion of the wavelength region and a non-light emitting quantum dot not emitting a visible light region, the difference between the LUMO energy level of the non-emitting quantum dot and the electron transport layer is about 0.5eV or more. .

The LUMO energy level of the non-light emitting quantum dot may be about 0.5 eV or more lower than the LUMO energy level of the electron transport layer.

The LUMO energy level of the non-light emitting quantum dot may be about 0.5 eV to 1.5 eV lower than the LUMO energy level of the electron transport layer.

An energy band gap of the non-emitting quantum dots may be greater than an energy band gap of the light emitting quantum dots.

The energy bandgap of the non-emitting quantum dot may be about 3.0 eV or more.

The LUMO energy level of the non-light emitting quantum dot may be smaller than the LUMO energy level of the light emitting quantum dot and the LUMO energy level of the electron transport layer, respectively.

The diameter of the non-light emitting quantum dots may be smaller than the diameter of the light emitting quantum dots.

The quantum dot layer may include a mixture of the light emitting quantum dots and the non-light emitting quantum dots.

The non-emitting quantum dots may be included less than the light emitting quantum dots.

The non-emitting quantum dots may be included in about 20% by weight or less based on the total content of the light emitting quantum dots and the non-emitting quantum dots.

The quantum dot layer may include a first quantum dot layer including the light emitting quantum dot, and a second quantum dot layer including the non-light emitting quantum dot.

The second quantum dot layer may be thinner than the first quantum dot layer.

The thickness of the second quantum dot layer may be about 20 nm or less.

The first quantum dot layer may be closer to the electron transport layer than the second quantum dot layer.

HOMO energy level of the light emitting quantum dot may be about 5.3eV to 7.5eV.

The light emitting quantum dots may be quantum dots of a core-shell structure, and the non-light emitting quantum dots may be quantum dots of a core structure.

The core of the light emitting quantum dot may include zinc (Zn), tellurium (Te), and selenium (Se), and the shell of the light emitting quantum dot may include ZnSeS, ZnS, or a combination thereof.

The non-light emitting quantum dot may include ZnS, ZnSe, ZnTe, CdS, or a combination thereof.

A hole transport layer may be further included between the anode and the quantum dot layer, and the HOMO energy level of the hole transport layer may be about 5.2 eV to 7.3 eV.

According to another embodiment, an electronic device including the quantum dot device is provided.

The performance of the quantum dot device can be improved.

1 is a schematic cross-sectional view of a quantum dot device according to an embodiment;
FIG. 2 is a schematic diagram of a light emitting quantum dot and a non-light emitting quantum dot included in the quantum dot layer of the quantum dot element of FIG. 1,
3 is an energy diagram illustrating an energy level of the quantum dot device of FIG.
4 is a schematic cross-sectional view of a quantum dot device according to another embodiment;
FIG. 5 is an energy diagram exemplarily illustrating an energy level of the quantum dot device of FIG. 4.

Hereinafter, embodiments will be described in detail so that those skilled in the art can easily implement the embodiments. However, the scope of rights may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a portion of a layer, film, region, plate, etc. is said to be "on top" of another part, this includes not only when the other part is "right over" but also when there is another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

Hereinafter, the values of the work function (WF), the HOMO energy level and the LUMO energy level are expressed as absolute values from the vacuum level. In addition, the work function, HOMO energy level or LUMO energy level is deep, high or large means that the absolute value is large with the vacuum level '0eV' and the work function, HOMO energy level or LUMO energy level is shallow, low or small. Means that the absolute value is small with the vacuum level '0eV'.

Hereinafter, a quantum dot device according to an embodiment is described with reference to the drawings.

1 is a cross-sectional view schematically illustrating a quantum dot device according to an embodiment, FIG. 2 is a schematic view of a light emitting quantum dot and a non-light emitting quantum dot included in the quantum dot layer of the quantum dot device of FIG. 1, and FIG. 3 is a quantum dot device of FIG. 1. An energy diagram illustrating the energy level of an example.

Referring to FIG. 1, the quantum dot device 10 according to an embodiment includes an anode 11 and a cathode 12 facing each other, an electron transport layer 13 disposed between the anode 11 and the cathode 12, A quantum dot layer 14, a hole transport layer 15, and a hole injection layer 16.

The substrate (not shown) may be disposed on the anode 11 side or disposed on the cathode 12 side. The substrate may be, for example, an inorganic material such as glass; Organic materials such as polycarbonate, polymethylmethacrylate, polyethylene terephthalate, polyethylenenaphthalate, polyamide, polyethersulfone or combinations thereof; Or a silicon wafer.

The anode 11 may be made of a conductor having a relatively high work function to facilitate hole injection, for example, a metal, a conductive metal oxide, or a combination thereof. The anode 11 is, for example, a metal such as nickel, platinum, vanadium, chromium, copper, zinc, gold or an alloy thereof; Conductive metal oxides such as zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO) or fluorine doped tin oxide; Or a combination of a metal and an oxide such as ZnO and Al or SnO ₂ and Sb, but is not limited thereto.

The cathode 12 may be made of a conductor having a relatively low work function, for example, to facilitate electron injection, and may be made of a metal, a conductive metal oxide and / or a conductive polymer, for example. The cathode 12 may be, for example, a metal such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, lead, cesium, barium, or an alloy thereof; Multilayer structure materials such as LiF / Al, LiO ₂ / Al, LiF / Ca, Liq / Al, and BaF ₂ / Ca, but are not limited thereto.

At least one of the anode 11 and the cathode 12 may be a light transmitting electrode, which may be, for example, zinc oxide, indium oxide, tin oxide, indium tin oxide (ITO), indium zinc oxide (IZO) or fluorine doped tin. It can be made of a conductive metal oxide, such as an oxide, or a thin or single layer or multiple layers of metal thin films. When one of the anode 11 and the cathode 12 is an opaque electrode, it may be made of an opaque conductor such as aluminum (Al), silver (Ag) or gold (Au), for example.

The electron transport layer 13 is located on one surface of the cathode 12 and may include one layer or two or more layers. The electron transport layer 13 may include, for example, an inorganic material, an organic material, and / or an inorganic material.

The LUMO energy LUMO _ETL of the electron transport layer 13 may be equal to or less than the work function WF _c of the cathode 12, for example, the LUMO energy LUMO _ETL and cathode 12 of the electron transport layer 13. The difference in the work function WF _c of may be about 0.5 eV or less. For example, the LUMO energy (LUMO _ETL ) of the electron transport layer 13 may be about 2.5 eV to 4.3 eV, and may be, for example, about 2.7 eV to 4.0 eV and about 2.7 eV to 3.8 eV within the above range.

The electron transport layer 13 is, for example, 1,4,5,8-naphthalene-tetracarboxylic dianhydride (1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA), bathocuproine (BCP) , Tris [3- (3-pyridyl) -mesityl] borane (3TPYMB), LiF, Alq3, Gaq3, Inq3, Znq2, Zn (BTZ) 2, BeBq2, ET204 (8- (4- (4,6) -di (naphthalen-2-yl) -1,3,5-triazin-2-yl) phenyl) quinolone), 8-hydroxyquinolinato lithium (Liq), n-type metal oxide (e.g., ZnO, HfO _2, etc.) And at least one selected from a combination thereof, but is not limited thereto.

Quantum dot layer 14 includes light emitting quantum dots 14a and non-light emitting quantum dots 14b. For example, the light emitting quantum dots 14a and the non-light emitting quantum dots 14b may be present in a mixture in the quantum dot layer 14.

The light emitting quantum dots 14a may be quantum dots emitting light in at least some wavelength regions of the visible light region, and may be, for example, quantum dots emitting blue light, red light, or green light, where the blue light peaks at, for example, about 430 nm to 470 nm. emission wavelength (peak emission wavelength, λ _max) can have and the red light is about 620nm to at 660nm can have a peak emission wavelength (λ _max), and a green light for example, the peak emission wavelength (λ _max) at about 510nm to about 550nm a Can have. The emission wavelength of the emission quantum dot 14a may be determined according to the size and / or composition.

The light emitting quantum dots 14a may have a relatively narrow full width at half maximum (FWHM). Here, the half value width is a width of a wavelength corresponding to a half of a peak emission point, and when the half value width is small, it means that light of a narrow wavelength range can be emitted to exhibit high color purity. The quantum dots can have a half width of about 50 nm or less, for example, within the range of about 49 nm or less, about 48 nm or less, about 47 nm or less, about 46 nm or less, about 45 nm or less, about 44 nm or less, about 43 nm or less, about 42 nm or less, About 41 nm or less, about 40 nm or less, about 39 nm or less, about 38 nm or less, about 37 nm or less, about 36 nm or less, about 35 nm or less, about 34 nm or less, about 33 nm or less, about 32 nm or less, about 31 nm or less, about 30 nm or less, about 29 nm It may have a half width of less than or about 28 nm.

The non-emitting quantum dot 14b may be a quantum dot that does not emit light in the visible light region. The non-light-emitting quantum dot 14b is not particularly limited with respect to light in an invisible light region, such as an infrared and / or ultraviolet region.

The light emitting quantum dots 14a and the non-light emitting quantum dots 14b may each have a particle diameter of about 1 nm to about 100 nm (the size of the longest part, if not spherical), for example, may have a particle diameter of about 1 nm to 80 nm, For example, it may have a particle size of about 1 nm to 50 nm, may have a particle size of about 1 nm to 40 nm, for example, may have a particle size of about 1 nm to 30 nm, and may have a particle size of about 1 nm to 20 nm, for example. In this case, the particle diameter of the non-light emitting quantum dot 14b may be smaller than the particle diameter of the light emitting quantum dot 14a. For example, the particle diameter of the non-light emitting quantum dot 14b may be about 0.1 to 0.9 times the particle diameter of the light emitting quantum dot 14a. Within a range such as about 0.2 to 0.8 times, such as about 0.2 to 0.7 times, such as about 0.2 to 0.6 times, such as about 0.2 to 0.5 times.

The light emitting quantum dots 14a and the non-light emitting quantum dots 14b may each be semiconductor nanocrystals having a broad meaning, and may have various shapes such as isotropic semiconductor nanocrystals, quantum rods, and quantum plates. The light emitting quantum dots 14a and the non-light emitting quantum dots 14b are each independently, for example, group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductor compounds, and I-III- Group VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. Group II-VI semiconductor compounds include, for example, binary element semiconductor compounds selected from CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS and mixtures thereof; CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnSe, HgZnSe ; And an elemental semiconductor compound selected from ZnSeSTe, HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof. Group III-V semiconductor compounds include, for example, binary element semiconductor compounds selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb and mixtures thereof; Three-element semiconductor compounds selected from GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, and mixtures thereof; And an isotropic semiconductor compound selected from GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof. It is not. Group IV-VI semiconductor compounds include, for example, binary element semiconductor compounds selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof; Three-element semiconductor compounds selected from SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; And an elementary semiconductor compound selected from SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof, but is not limited thereto. Group IV semiconductor compounds include, for example, unsubstituted semiconductor compounds selected from Si, Ge and mixtures thereof; And a two-element semiconductor compound selected from SiC, SiGe, and mixtures thereof, but is not limited thereto. The group I-III-VI semiconductor compound may be selected from, for example, CuInSe ₂ , CuInS ₂ , CuInGaSe, CuInGaS, and mixtures thereof, but is not limited thereto. The group I-II-IV-VI semiconductor compound may be selected from, for example, CuZnSnSe and CuZnSnS, but is not limited thereto. The II-III-V semiconductor compound may include, but is not limited to, InZnP.

Each of the light emitting quantum dots 14a and the non-light emitting quantum dots 14b independently includes the above-described binary element compound, tertiary element compound or element element semiconductor compound in a substantially uniform concentration, or in a state where the concentration distribution is partially different. It can be divided and included.

For example, the light emitting quantum dots 14a and the non-light emitting quantum dots 14b may include non-cadmium-based quantum dots, respectively. Cadmium (Cd) can cause serious environmental / health problems and, in many countries, non-cadmium-based quantum dots can be used effectively because it is a regulated element under the Restriction of Hazardous Substances Directive (RoHS).

For example, the light emitting quantum dot 14a may have a core-shell structure including a core 14aa and a shell 14ab, as shown in FIG. 2A. For example, the material composition constituting the shell 14ab of the light emitting quantum dot 14a may have a higher energy bandgap than the material composition constituting the core 14aa of the light emitting quantum dot 14a, thereby quantum confinement effect. It can have a light emitting. For example, the shell 14ab of the light emitting quantum dot 14a may be one layer or a multilayer, for example, a shell located far from the core of the multilayer shell may have a higher energy bandgap than a shell located closer to the core, Accordingly, it may have a quantum confinement effect. The material constituting the core 14aa of the light emitting quantum dot 14a and the material constituting the shell 14ab may be different from each other, and may be selected from the above-described semiconductor compounds within a range capable of producing a quantum confinement effect.

For example, the light emitting quantum dot 14a may be formed on a core including a Zn-Te-Se based semiconductor compound including, for example, zinc (Zn), tellurium (Te), and selenium (Se), and at least a portion of the core. And a shell including a second semiconductor compound positioned and having a composition different from that of the core. The light emitting quantum dot 14a of the core-shell structure may emit blue light having a peak emission wavelength in a wavelength region of about 470 nm or less, for example, in a wavelength region of about 430 nm to 470 nm.

The first semiconductor compound based on Zn-Te-Se may be a Zn-Se based semiconductor compound including, for example, a small amount of tellurium (Te), such as ZnTe _x Se _{1 - x} , where x is greater than 0 and 0.05 Or a semiconductor compound represented by the following).

For example, in a Zn-Te-Se based first semiconductor compound, the molar content of zinc (Zn) may be higher than that of selenium (Se), and the molar content of selenium (Se) is molar content of tellurium (Te). Can be more. For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to selenium (Se) is about 0.05 or less, about 0.049 or less, about 0.048 or less, about 0.047 or less, about 0.045 or less, about 0.044 or less, about 0.043 or less, about 0.042 or less, about 0.041 or less, about 0.04 or less, about 0.039 or less, about 0.035 or less, about 0.03 or less, about 0.029 or less, about 0.025 or less, about 0.024 or less, about 0.023 or less, about 0.022 or less, about 0.021 or less, about 0.02 or less , About 0.019 or less, about 0.018 or less, about 0.017 or less, about 0.016 or less, about 0.015 or less, about 0.014 or less, about 0.013 or less, about 0.012 or less, about 0.011 or less, or about 0.01 or less. For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to zinc (Zn) is about 0.02 or less, about 0.019 or less, about 0.018 or less, about 0.017 or less, about 0.016 or less, about 0.015 or less, about 0.014 or less, about 0.013 or less, about 0.012 or less, about 0.011 or less, or about 0.011 or less.

The second semiconductor compound may be selected, for example, from a semiconductor compound having an energy bandgap larger than that of the first semiconductor compound, such as a Group II-VI semiconductor compound, Group III-V semiconductor compound, IV satisfying such an energy bandgap. Group-VI-VI semiconductor compounds, Group IV semiconductor compounds, Group I-III-VI semiconductor compounds, Group I-II-IV-VI semiconductor compounds, Group II-III-V semiconductor compounds, or combinations thereof. . Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group IV-VI semiconductor compounds, Group IV semiconductor compounds, Group I-III-VI semiconductor compounds, Group I-II-IV-VI semiconductor compounds, and Examples of the II-III-V semiconductor compound are as described above. For example, the second semiconductor compound may include zinc (Zn), selenium (Se), and / or sulfur (S). For example, the shell may comprise ZnSeS and / or ZnS. For example, the shell may have a concentration gradient with respect to one component and, for example, a concentration gradient in which the content of sulfur (S) increases as the distance from the core increases.

For example, the light emitting quantum dot 14a is positioned on at least a portion of the core and the core including, for example, an In—Zn—P based third semiconductor compound including indium (In), zinc (Zn), and phosphorus (P). It may include a shell comprising a fourth semiconductor compound having a composition different from the core. The light emitting quantum dot 14a of the core-shell structure may emit blue light, green light, or red light. For example, blue light may emit blue light having a peak emission wavelength in a wavelength region of about 470 nm or less, such as in a wavelength region of about 430 nm to 470 nm.

The molar ratio of zinc (Zn) to indium (In) in the In—Zn—P based third semiconductor compound may be about 25 or more. For example, the molar ratio of zinc (Zn) to indium (In) in the first semiconductor compound of In—Zn—P may be about 28 or more, 29 or more, or 30 or more. For example, the molar ratio of zinc (Zn) to indium (In) in the In-Zn-P based first semiconductor compound may be about 55 or less, for example, 50 or less, 45 or less, 40 or less, 35 or less, 34 or less, 33 Or 32 or less.

The fourth semiconductor compound may be selected, for example, from a semiconductor compound having an energy bandgap larger than that of the third semiconductor compound, such as, for example, Group II-VI semiconductor compounds, Group III-V semiconductor compounds, satisfying such energy bandgap, Group IV-Group VI semiconductor compounds, Group IV semiconductor compounds, Group I-III-VI semiconductor compounds, Group I-II-IV-VI semiconductor compounds, Group II-III-V semiconductor compounds, or combinations thereof have. Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group IV-VI semiconductor compounds, Group IV semiconductor compounds, Group I-III-VI semiconductor compounds, Group I-II-IV-VI semiconductor compounds, and Examples of the II-III-V semiconductor compound are as described above. For example, the fourth semiconductor compound may include zinc (Zn) and sulfur (S) and optionally selenium (Se). For example, the shell may include one or more inner shells located close to the core and an outermost shell located at the outermost side of the quantum dots, and at least one of the inner shell and the outermost shell may include a fourth semiconductor compound of ZnS or ZnSeS. Can be.

For example, the non-light emitting quantum dot 14b may have a shellless core structure as shown in FIG. 2B. Accordingly, unlike the light emitting quantum dot 14a, the non-light emitting quantum dot 14b may not emit light because it may not have a quantum confinement effect. The non-emitting quantum dots 14b may be selected from the above-described semiconductor compounds, and for example, Group II-VI semiconductor compounds, Group III-V semiconductor compounds, Group IV-VI semiconductor compounds, Group IV semiconductor compounds, Group I- Group III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof, including, for example, ZnS, ZnSe, ZnTe, CdS, or combinations thereof. can do.

The light emitting quantum dots 14a and the non-light emitting quantum dots 14b may have different energy levels. For example, the energy band gap of the non-light emitting quantum dots 14b may be larger than the energy band gap of the light emitting quantum dots 14a. For example, the energy bandgap of the non-emitting quantum dot 14b may be about 3.0 eV or more, and within the above range, for example, about 3.1 eV or more, about 3.2 eV or more, about 3.4 eV or more, about 3.6 eV or more, or about 3.8 eV or more. Or about 4.0 eV or more, and within this range such as about 3.0 eV to 5.5 eV, about 3.1 eV to 5.5 eV, about 3.2 eV to 5.5 eV, about 3.4 eV to 5.5 eV, about 3.6 eV to 5.5 eV, about 3.8 eV to 5.5 eV or about 4.0 eV to 5.5 eV.

As an example, the LUMO energy level LUMO _{QD 14b of the} non-light-emitting quantum dot 14b may be smaller than the LUMO energy level LUMO _{QD 14a of the} light-emitting quantum dot _14a , for example, of the non-light-emitting quantum dot 14b. The LUMO energy level (LUMO _{QD 14b)} is about 0.2 eV or more, about 0.4 eV or more, about 0.5 eV or more, about 0.7 eV or more, or about 0.9 above the LUMO energy level (LUMO _QD 14a) of the light emitting quantum dot 14a. eV or more, and may be as small as in the range of about 0.2 eV to 1.5 eV, about 0.4 eV to 1.5 eV, about 0.5 eV to 1.5 eV, about 0.7 eV to 1.5 eV, or about 0.9 eV to 1.5 eV. .

For example, the LUMO energy level LUMO _{QD 14b of the} non-light emitting quantum dot 14b may be different from the LUMO energy level LUMO _ETL of the electron transport layer 13, and the non-light emitting quantum dot 14b and the electron transport layer 13 may be different from each other. The difference (Δd) of the LUMO energy level of) may be, for example, about 0.5 eV or more. For example, the difference Δd between the LUMO energy levels of the non-light emitting quantum dot 14b and the electron transport layer 13 may be, for example, about 0.5 eV to 1.5 eV. For example, the LUMO energy level (LUMO _{QD 14b) of the} non-light-emitting quantum dot 14b may be about 0.5 eV or more smaller than the LUMO energy level of the electron transport layer 13, for example, the LUMO energy level of the non-light-emitting quantum dot 14b may be For example, it may be about 0.5 eV to 1.5 eV smaller than the LUMO energy level of the electron transport layer 13.

For example, the LUMO energy level of the non-light emitting quantum dots (14b) LUMO energy level (LUMO _{QD (14b))} are light emitting quantum dots LUMO energy level (LUMO _{QD (14a))} and an electron transport layer 13 of the (14a) of (LUMO _ETL ) than can be smaller, respectively, such as non-LUMO of the light emitting quantum dot (14b) LUMO energy level (LUMO _{QD (14b a))} is (LUMO energy level of 14a) (LUMO _{QD (14a)} light-emitting quantum dots) and an electron transport layer 13 LUMO energy level of the energy level (LUMO _ETL) may be less than at least about 0.5eV, for example, the LUMO energy level of the non-light emitting quantum dots _{(14b) (LUMO QD (14b} )) are light emitting quantum dots _{(14a) (LUMO QD (14a} )) And about 0.5 eV to about 1.5 eV smaller than the LUMO energy level (LUMO _ETL ) of the electron transport layer 13. Due to the low LUMO energy level of the non-emitting quantum dots 14b, the non-emitting quantum dots 14b act as a barrier to electrons moving from the electron transport layer 13 to the quantum dot layer 14, thereby lowering electron mobility. have.

In general, in the quantum dot device, the mobility of holes and electrons may be different, for example, the mobility of electrons may be higher than the mobility of holes. Thus, there may be a mobility imbalance between the holes moving from the anode 11 to the quantum dot layer 14 and the electrons moving from the cathode 12 to the quantum dot layer 14, whereby relatively fast electrons At the light emitting point of the quantum dot layer 14, the quantum dot layer 14 may accumulate at the interface between the quantum dot layer 14 and the hole transport layer 15. As such, the electrons accumulated at the interface between the quantum dot layer 14 and the hole transport layer 15 may degrade the quantum dot device and shorten the life of the quantum dot device.

In this embodiment, the non-light-emitting quantum dot 14b having a relatively low LUMO energy level may be included in the quantum dot layer 14 to control mobility of electrons moving from the electron transport layer 13 to the quantum dot layer 14. Accordingly, the mobility of the quantum dot device is improved by balancing the mobility between the holes moving from the anode 11 to the quantum dot layer 14 and the electrons moving from the cathode 12 to the quantum dot layer 14. It is possible to prevent the accumulation of electrons at the interface between the 14 and the hole transport layer 15 to improve the life characteristics of the quantum dot device.

HOMO energy level (HOMO _{QD (14a))} and the HOMO energy level (HOMO _{QD (14b))} of the non-light emitting quantum dots (14b) of the light-emitting quantum dots (14a) may be the same or different. HOMO energy level of the quantum dot light-emitting _{(14a) (HOMO QD (14a} )) and non-HOMO energy level (HOMO _{QD (14b))} of the light-emitting quantum dots (14b) may be relatively high, for example greater than about 5.2eV, about 5.4eV or more For example, at least about 5.5 eV, at least about 5.6 eV, at least about 5.7 eV, at least about 5.8 eV, such as at least about 5.9 eV, such as at least about 6.0 eV. HOMO energy level of the quantum dot light-emitting _{(14a) (HOMO QD (14a} )) and the HOMO energy level (HOMO _{QD (14b)),} for example from about 5.2eV to 7.3eV, such as about 5.4 within the range of the non-light emitting quantum dots (14b) eV to 7.3 eV, such as about 5.4 eV to 7.1 eV, such as about 5.4 eV to 7.0 eV, such as about 5.6 eV to 7.0 eV, such as about 5.6 eV to 6.8 eV, such as about 5.6 eV to 6.7 eV, such as about 5.6 eV to 6.5 eV, such as about 5.6 eV to 6.3 eV, such as about 5.6 eV to 6.2 eV, such as about 5.6 eV to 6.1 eV, such as about 5.8 eV to 7.0 eV, such as about 5.8 eV to 6.8 eV, such as about 5.8 eV to 6.7 eV For example, about 5.8 eV to 6.5 eV, such as about 5.8 eV to 6.3 eV, such as about 5.8 eV to 6.2 eV, such as about 5.8 eV to 6.1 eV, such as about 6.0 eV to 7.0 eV, such as about 6.0 eV to 6.8 eV, such as About 6.0 eV to 6.7 eV, such as about 6.0 eV to 6.5 eV, such as about 6.0 eV to 6.3 eV, such as about 6.0 eV to 6.2 eV.

As described above, the light emitting quantum dots 14a and the non-light emitting quantum dots 14b may exist in the form of a mixture in the quantum dot layer 14, where the non-light emitting quantum dots 14b may include less than the light emitting quantum dots 14a. have. For example, the non-light-emitting quantum dots 14b may be included in less than about 50% by weight relative to the total content of the light-emitting quantum dots 14a and the non-light-emitting quantum dots 14b, such as about 40% by weight, about 30% by weight or Up to about 20% by weight.

The quantum dot layer 14 may have a thickness of, for example, about 5 nm to 200 nm, may have a thickness of, for example, about 10 nm to 150 nm, within the range, for example, may have a thickness of, for example, about 10 nm to 100 nm, Within this range, for example, it may have a thickness of about 15 nm to 80 nm, within this range, for example, it may have a thickness of about 20 nm to 50 nm, and within this range, for example, it may have a thickness of about 25 nm to 40 nm.

The hole transport layer 15 and the hole injection layer 16 may be positioned between the anode 11 and the quantum dot layer 14, and the hole transport layer 15 is located on the quantum dot layer 14 side, and the hole injection layer 16 is located. Is positioned on the anode 11 side and holes supplied from the anode 11 may be transferred to the quantum dot layer 14 through the hole injection layer 16 and the hole transport layer 15. For example, the hole transport layer 15 may be in contact with the quantum dot layer 14, and the hole injection layer 16 may be in contact with the anode 11.

The HOMO energy level HOMO _HIL of the hole injection layer 16 may be between the work function of the anode 11 and the HOMO energy level of the quantum dot layer 14, for example, about 5.0 eV to 5.5 eV.

The hole injection layer 16 may include a conductive compound, and may include, for example, a conductive metal oxide, a conductive monomer, a conductive oligomer, a conductive polymer, and / or a conductive ion compound, for example, a conductivity of about 1 × 10 ⁻⁷ S / cm or more. Conductive metal oxides, conductive monomers, conductive oligomers, conductive polymers and / or conductive ionic compounds, including, for example, conductive oxides, conductive monomers, conductive materials having a conductivity of about 1 × 10 ⁻⁷ S / cm to 1000 S / cm Oligomers, conductive polymers and / or conductive ionic compounds. Conductive compounds are, for example, polythiophene, polyaniline, polypyrrole, poly (para-phenylene), polyfluorene, poly (3,4-ethylenedioxythiophene), poly (3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT: PSS), derivatives thereof, or combinations thereof, but is not limited thereto.

HOMO energy level (HOMO _HTL) of the hole transport layer 15 is a hole injection layer, the HOMO energy level (HOMO _{QD (14a} of the light-emitting quantum dots (14a) of the HOMO energy level (HOMO _HIL) and the quantum dot layer 14 of ₁₆₎ ) As a result, a stepped energy level can be formed from the hole injection layer 16 to the quantum dot layer 14, so that the mobility of holes can be effectively increased.

HOMO energy level (HOMO _HTL), a hole transporting layer 15 like the quantum dot layer 14 so as to be matched with the HOMO energy level (HOMO _{QD (14a))} of the light-emitting quantum dots (14a) of the quantum dot layer 14 is a relatively high It may have a HOMO energy level.

For example, differences in the hole transporting layer (15) HOMO energy level (HOMO _HTL) and the quantum dot layer 14, a quantum dot light-emitting (14a) HOMO energy level (HOMO _{QD (14a))} of the a may be up to about 0.5eV, the In the range of about 0 eV to 0.5 eV, about 0.01 eV to 0.4 eV, such as about 0.01 eV to 0.3 eV, such as about 0.01 eV to 0.2 eV, such as about 0.01 eV to 0.1 eV. For example, the HOMO energy level (HOMO _HTL) of the hole transport layer 15 is equal to the HOMO energy level (HOMO _{QD (14a))} of the light-emitting quantum dots (14a) of the quantum dot layer 14, or less than within a range of about 0.5eV or less Can be small.

For example, the HOMO energy level HOMO _HTL of the hole transport layer 15 may be, for example, about 5.4 eV or more, within the range, for example, about 5.6 eV or more, and within the range, for example, about 5.8 eV or more. For example, the HOMO energy level (HOMO _HTL ) of the hole transport layer 15 may be about 5.4 eV to 7.0 eV, and within this range, for example, about 5.4 eV to 6.8 eV, such as about 5.4 eV to 6.7 eV, such as about 5.4 eV to 6.5 eV, such as about 5.4 eV to 6.3 eV, such as about 5.4 eV to 6.2 eV, such as about 5.4 eV to 6.1 eV, such as about 5.6 eV to 7.0 eV, such as about 5.6 eV to 6.8 eV, such as about 5.6 eV to 6.7 eV For example, about 5.6 eV to 6.5 eV, such as about 5.6 eV to 6.3 eV, such as about 5.6 eV to 6.2 eV, such as about 5.6 eV to 6.1 eV, such as about 5.8 eV to 7.0 eV, such as about 5.8 eV to 6.8 eV, such as About 5.8 eV to 6.7 eV, such as about 5.8 eV to 6.5 eV, such as about 5.8 eV to 6.3 eV, such as about 5.8 eV to 6.2 eV, such as about 5.8 eV to 6.1 eV.

The hole transport layer 15 is not particularly limited as long as it is a material that satisfies the energy level. For example, poly (9,9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine) (Poly ( 9,9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine), TFB), polyarylamine, poly (N-vinylcarbazole) (poly (N-vinylcarbazole), polyaniline, polypyrrole (polypyrrole), N, N, N ', N'-tetrakis (4-methoxyphenyl) -benzidine (N, N, N', N'-tetrakis (4-methoxyphenyl) -benzidine, TPD), 4- Bis [N- (1-naphthyl) -N-phenyl-amino] biphenyl (4-bis [N- (1-naphthyl) -N-phenyl-amino] biphenyl, α-NPD), m-MTDATA (4 , 4 ', 4 "-Tris [phenyl (m-tolyl) amino] triphenylamine), 4,4', 4" -tris (N-carbazolyl) -triphenylamine (4,4 ', 4 "-tris ( N-carbazolyl) -triphenylamine, TCTA), 1,1-bis [(di-4-toylamino) phenylcyclohexane (TAPC), p-type metal oxide (eg, NiO, WO ₃ , MoO _3, etc.), At least selected from carbon-based materials such as graphene oxide and combinations thereof It may include, but me, and the like.

4 is a schematic cross-sectional view of a quantum dot device according to another embodiment.

Referring to FIG. 4, the quantum dot device 10 according to the present embodiment is positioned between the anode 11 and the cathode 12 and the anode 11 and the cathode 12 facing each other, as in the above-described embodiment. And an electron transport layer 13, a quantum dot layer 14, a hole transport layer 15, and a hole injection layer 16.

However, unlike the above-described embodiment, the quantum dot device according to the present embodiment has a quantum dot layer 14 positioned close to the electron transport layer 13 and includes a first quantum dot layer 14-1 and a hole transport layer including the light emitting quantum dots 14a. And a second quantum dot layer 14-2 positioned close to 15) and comprising a non-emitting quantum dot 14b.

The first quantum dot layer 14-1 may include the above-described light emitting quantum dot 14a and include a light emitting point at which holes supplied from the anode 11 and electrons supplied from the cathode 12 combine to emit light. Can be.

The second quantum dot layer 14-2 may include the non-light emitting quantum dots 14b described above and do not include a light emitting point. LUMO energy level of the LUMO energy level 2 of the non-light emitting quantum dots (14b) included in the quantum dot layer _{(14-2) (LUMO QD (14b} )) are light emitting quantum dots (14a) as described above (LUMO _{QD (14a))} As it is smaller, the mobility of the electrons may be reduced and / or blocked, thereby preventing the electrons passing through the first quantum dot 14-1 from entering the hole transport layer 15. That is, the second quantum dot layer 14-2 serves as an electron blocking layer so that electrons accumulate at the interface between the quantum dot layer 14 and the hole transport layer 15 or charge to the hole transport layer 15. Can be prevented from moving to reduce and / or prevent degradation of the quantum dot element.

The second quantum dot layer 14-2 may be thinner than the first quantum dot layer 14-1. The thickness of the second quantum dot layer 14-2 may be about 20 nm or less, and may be, for example, about 1 nm to 20 nm, about 1 nm to 18 nm, about 1 nm to 15 nm, about 1 nm to 12 nm, and about 1 nm to 10 nm within the above range. It is not limited to this.

The above-mentioned electron transport layer 13, quantum dot layer 14, hole transport layer 15 and hole injection layer 16 may be formed by, for example, a solution process or a deposition process, the solution process is, for example, spin coating, slit coating, inkjet It may be formed by printing, nozzle printing, spraying and / or doctor blade coating, but is not limited thereto.

The quantum dot device may be applied to various electronic devices such as a display device or an illumination device.

The embodiments described above will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only and do not limit the scope of the rights.

Quantum dots  synthesis

Synthesis Example  One

Step 1: ZnTeSe  Synthesis of core

Selenium (Se) and tellurium (Te) are dispersed in trioctylphosphine (TOP) to obtain 2M Se / TOP stock solution and 0.1M Te / TOP stock solution. 0.125 mmol of zinc acetate together with 0.25 mmol of palmitic acid and 0.25 mmol of hexadecylamine are placed in a reactor with 10 mL of trioctylamine and heated to 120 degrees under vacuum. After 1 hour the atmosphere in the reactor is switched to nitrogen. After heating to 300 degrees, the Se / TOP stock solution and Te / TOP stock solution prepared above are rapidly injected with a Te / Se ratio of 1/25. After 10 minutes, 30 minutes, or 60 minutes, acetone was added to the reaction solution cooled to room temperature rapidly, and the precipitate obtained by centrifugation was dispersed in toluene to obtain a ZnTeSe quantum dot.

Step 2: ZnTeSe  core/ ZnSeS Shell Quantum dots  synthesis

1.8mmoL of zinc acetate (0.336g), 3.6mmol of oleic acid (1.134g) and 10mL of trioctylamine are added to the flask and vacuumed at 120 ° C for 10 minutes. The flask was replaced with nitrogen (N ₂ ) and then heated to 180 ° C. Here, the ZnTeSe core obtained in Synthesis Example 1 was added within 10 seconds, and then 0.04 mmol of Se / TOP was slowly injected, followed by heating to 280 ° C. Thereafter, 0.01 mmol of S / TOP was added, and the reaction mixture was heated to 320 ° C. for 10 minutes. Successively, 0.02 mmol of Se / TOP and 0.04 mmol of S / TOP mixture are slowly injected and reacted again for 20 minutes. After changing the mixing ratio of Se and S and repeat the step of reacting for 20 minutes, the mixed solution of Se and S used is a mixed solution of Se / TOP 0.01mmol + S / TOP 0.05mmol, Se / TOP 0.005mmol + A mixed solution of S / TOP 0.1 mmol (B) and 0.5 mmol S / TOP solution, these are used in this order. After the reaction was completed, the reactor was cooled, and the prepared nanocrystals were centrifuged with ethanol and dispersed in toluene to obtain ZnTeSe / ZnSeS coreshell quantum dots.

Synthesis Example  2: ZnS  Manufacture of core

Disperse sulfur in trioctylphosphine (TOP) to prepare 1M S / TOP stock solution. Diethylzinc is dissolved in hexane to give 1M Zn stock solution. In a 300 mL reaction flask, the organic ligand containing oleic acid and diethylzinc stock solution are dissolved in trioctylamine and heated to 120 ° C. under vacuum. Replace the flask with an inert gas, inject S / TOP stock solution, and raise the temperature to 300 ℃ to react for 40 minutes. After the reaction, ethanol was added to the reaction solution cooled to room temperature and centrifuged to recover ZnS core particles. The recovered ZnS core particles are dispersed in toluene. The content ratio (Zn: S, molar ratio) of Zn precursor and S precursor used is approximately 2: 1.

Quantum dots  Fabrication of the Device I

Example  One

After 15 minutes of surface treatment with UV-ozone on a glass substrate on which ITO (WF: 4.8 eV) was deposited, spin-coated a PEDOT: PSS solution (HC Starks) and heat-treated at 150 degrees for 10 minutes in an air atmosphere. Heat treatment at 150 ° C. for 10 minutes in N ₂ atmosphere forms a hole injection layer (HOMO: 5.3 eV, LUMO: 2.7 eV) having a thickness of 25 nm. Subsequently, a hole transport material (Poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (4,4 ′-(N- (4-sec-butylphenyl) diphenylamine)] on the hole injection layer) and Sumitomo Chemical Co , Ltd.) spin-coated and heat-treated at 150 ° C. for 30 minutes to form a hole transport layer (HOMO: 5.6 eV, LUMO: 2.7 eV) having a thickness of 25 nm.The ZnTeSe / ZnSeS core obtained in Synthesis Example 1 was then formed on the hole transport layer. Quantum dot layer (HOMO) by spin coating a solution in which the shell-emitting quantum dots (peak emission wavelength: 453 nm) and the ZnS non-emitting quantum dots obtained in Synthesis Example 2 were mixed at a ratio of 95: 5 (wt: wt) and heat-treated at 150 degrees for 30 minutes. : 5.7 eV, LUMO: 3.0 eV) An electron transport material (an organic material including a mixture of anthracene based compounds and pyrazole compounds, Novaled) is vacuum deposited on the quantum dot layer to form a 40 nm thick electron transport layer (LUMO: 2.9 eV), vacuum deposition of Liq 5nm and aluminum (Al) 100nm thereon and a cathode to form a quantum dot device It is prepared.

Example  2

A quantum dot device was manufactured in the same manner as in Example 1, except that a quantum dot layer was formed using a solution in which a ZnTeSe / ZnSeS coreshell luminescent quantum dot and a ZnS non-emitting quantum dot were mixed at a ratio of 80:20 (wt: wt). .

Comparative example  One

A quantum dot device is manufactured in the same manner as in Example 1, except that the quantum dot layer includes only light emitting quantum dots instead of a mixture of light emitting quantum dots and non-light emitting quantum dots.

Evaluation I

The current-voltage-luminance characteristics of the quantum dot elements according to Examples 1 and 2 and Comparative Example 1 were evaluated.

Current-voltage-luminance characteristics are evaluated using a Keithley 220 current source and a Minolta CS200 spectroradiometer.

The results are shown in Table 1.

Example 1 Example 2 Comparative Example 1 EQE _max 3.2 4.6 1.9 EQE @ 100nit 3.0 4.5 1.5 EQE @ 500nit 3.0 3.5 1.9 Cd / A _max 2.2 3.3 1.2 Cd / ㎡ @ 5mA 105.7 158.2 44.2 λ _max 456 456 456 Half width (nm) 26 27 27 CIE x 0.143 0.143 0.145 CIE y 0.072 0.073 0.073

* EQE _max : Maximum external quantum efficiency

_* EQE @ 100nit: the external quantum efficiency at 100nit

_* EQE @ 500nit: the external quantum efficiency at 500nit

* Cd / A _max : maximum current efficiency

* Cd / ㎡ @ 5mA: luminance at 5mA

Referring to Table 1, the quantum dot device according to Examples 1 and 2 is compared with the quantum dot device according to Comparative Example 1 radiation It can be seen that the efficiency and brightness are improved.

Quantum dots  Fabrication of the Device II

Example  3

After 15 minutes of surface treatment with UV-ozone on a glass substrate on which ITO (WF: 4.8 eV) was deposited, spin-coated a PEDOT: PSS solution (HC Starks) and heat-treated at 150 degrees for 10 minutes in an air atmosphere. Heat treatment at 150 ° C. for 10 minutes in N ₂ atmosphere forms a hole injection layer (HOMO: 5.3 eV, LUMO: 2.7 eV) having a thickness of 25 nm. Subsequently, the hole transport material (poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (4,4 ′-(N- (4-sec-butylphenyl) diphenylamine)] on the hole injection layer) and Sumitomo Chemical Co , Ltd.) spin-coated and heat-treated at 150 ° C. for 30 minutes to form a hole transport layer (HOMO: 5.6 eV, LUMO: 2.7 eV) having a thickness of 25 nm, and then ZnS non-light-emitting quantum dots obtained in Synthesis Example 2 on the hole transport layer. Spin coating and heat treatment at 150 ° C. for 30 minutes to form a 5 nm thick lower quantum dot layer (HOMO: 6.3 eV, LUMO: 2.1 eV), followed by ZnTeSe / ZnSeS coreshell luminescent quantum dots obtained in Synthesis Example 1 on the lower quantum dot layer Spin-coating a peak emission wavelength of 453 nm) and heat-treating at 150 degrees for 30 minutes to form a 20 nm thick top quantum dot layer (HOMO: 5.7 eV, LUMO: 3.0 eV), followed by an electron transport material (anthracene-based) on the top quantum dot layer. 40 nm thick organic material, Novaled), containing a mixture of compounds and pyrazole compounds An electron transport layer (LUMO: 2.9 eV) was formed, and a cathode was formed by vacuum deposition of Liq 5 nm and 100 nm of aluminum (Al) thereon, thereby manufacturing a quantum dot device.

Comparative example  2

A quantum dot device was manufactured in the same manner as in Example 2, except that the lower quantum dot layer was not formed.

Evaluation II

The current-voltage-luminance characteristics of the quantum dot elements according to Example 3 and Comparative Example 2 were evaluated.

The results are shown in Table 2.

Example 3 Comparative Example 2 EQE _max 4.3 2.7 EQE @ 100nit 4.3 2.7 EQE @ 500nit 3.6 2.5 Cd / A _max 3.1 2.1 Cd / ㎡ @ 5mA 148.5 107.8 λ _max 457 457 Half width (nm) 30 31 CIE x 0.1448 0.1450 CIE y 0.0726 0.0825

Referring to Table 2, the quantum dot device according to Example 3 is compared with the quantum dot device according to Comparative Example 2 radiation It can be seen that the efficiency and brightness are improved.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of the invention.

11: anode
12: cathode
13: electron transport layer
14: quantum dot layer
15: hole transport layer
16: hole injection layer

Claims (20)

Anodes and cathodes facing each other,
A quantum dot layer located between the anode and the cathode, and
An electron transport layer located between the cathode and the quantum dot layer
Including,
The quantum dot layer includes a light emitting quantum dot that emits light in at least some wavelength region of the visible light region and a non-light emitting quantum dot that does not emit light in the visible light region,
The difference between the LUMO energy level of the non-emitting quantum dot and the electron transport layer is a quantum dot device of 0.5eV or more.
In claim 1,
The LUMO energy level of the non-light emitting quantum dot is 0.5eV or more smaller than the LUMO energy level of the electron transport layer.
In claim 2,
The LUMO energy level of the non-light-emitting quantum dot is 0.5eV to 1.5eV smaller than the LUMO energy level of the electron transport layer.
In claim 1,
The energy band gap of the non-emitting quantum dots is larger than the energy band gap of the light emitting quantum dots.
In claim 1,
The energy band gap of the non-light-emitting quantum dot is 3.0eV or more.
In claim 1,
The LUMO energy level of the non-light emitting quantum dot is smaller than the LUMO energy level of the light emitting quantum dot and the LUMO energy level of the electron transport layer, respectively.
In claim 1,
A particle size of the non-light emitting quantum dot is smaller than the particle size of the light emitting quantum dot.
In claim 1,
And the quantum dot layer comprises a mixture of the light emitting quantum dots and the non-light emitting quantum dots.
In claim 8,
The non-light emitting quantum dot is less quantum dot device than the light emitting quantum dot.
In claim 8,
The non-light emitting quantum dot is a quantum dot device that is contained in less than 20% by weight based on the total content of the light emitting quantum dot and the non-light emitting quantum dot.
In claim 1,
The quantum dot layer is
A first quantum dot layer comprising the light emitting quantum dots, and
A second quantum dot layer including the non-emitting quantum dots
Quantum dot device comprising a.
In claim 11,
And the second quantum dot layer is thinner than the first quantum dot layer.
In claim 11,
The second quantum dot layer has a thickness of 20 nm or less.
In claim 11,
And the first quantum dot layer is closer to the electron transport layer than the second quantum dot layer.
In claim 1,
HOMO energy level of the light emitting quantum dot is 5.3eV to 7.5eV quantum dot device.
In claim 1,
The light emitting quantum dot has a core-shell structure,
The non-emitting quantum dot has a core structure
Quantum dot device.
The method of claim 16,
The core of the light emitting quantum dot includes zinc (Zn), tellurium (Te) and selenium (Se),
The shell of the light emitting quantum dots includes ZnSeS, ZnS or a combination thereof.
Quantum dot device.
The method of claim 16,
The non-light-emitting quantum dot ZnS, ZnSe, ZnTe, CdS or a combination thereof.
In claim 1,
Further comprising a hole transport layer located between the anode and the quantum dot layer,
HOMO energy level of the hole transport layer is a quantum dot device of 5.2eV to 7.3eV.
An electronic device comprising the quantum dot device according to any one of claims 1 to 19.

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